Relationships between microstructural characteristics of materials and their physical-mechanical properties or behaviour under loading conditions.

1. Functional materials

Very high purity diamond single crystal growth / plasma reactors conception. Some recent major results can be highlighted :

Development for the first time of a growth model, validated experimentally, that allows to predict the crystal morphology, for a given thickness, as a function of the growth conditions ;

Pre-treatment and growth strategies that enable avoiding fracture and dislocation emergence during diamond growth, key point for growing thick crystals,

Progress in the reduction of the defects such as dislocations. This is still a bottleneck to overcome for developing power electronic switches, hole mobility as high as 1820 cm2/V s obtained on a low p doped (1.6 1015 at. cm-3) diamond crystal (top level international position).

New plasma process conception and reactor scale-up in order to improve significantly the growth process (uniformity and enlargement of the deposition surface), confirming the group top level position at the international level for both diamond deposition and plasma processes.

Development of a soft chemistry process that makes possible the in-situ homogeneous p-type and n-type doping of metal-oxide nanoparticles with a very narrow size distribution.

Deposition of doped metal-oxide nanoparticles with an improved absorption in the visible.

A major scientific achievement in bridging the gap between the mixing dynamic that characterize the elaboration process and the obtained nanoparticle size distribution. This required conducting a multidisciplinary research.

Demonstration of the potentiality of the elaborated materials in fields such as photonics, plasma-catalysis and photo-catalysis.

The study of electric-magnetic, magnetic-elastic, piezo-electric, optical properties extends over an open variety of compounds, in bulk and in (mono- or multi-) layered aspect, which are being given a controlled nano-structure. Models for micro-magnetic excitations in nanoscaled structures are being developed with special attention to the dimension reduction effects. For optic and acoustic investigations, Brillouin spectroscopy is among the techniques of which the laboratory has expertise and mastership, with the development of numerical simulations for the Brillouin spectra.

2. Structural Materials
Associating the activities of mechanists, metallurgists, chemists and physicists, are investigated all the steps along the elaboration/transformation - characterization/identification - modelling/simulation chain of materials. This diversity of disciplinary fields allows obtaining realistic descriptions of the overall material behaviour under applied or suffered loads, from the identified responsible elementary mechanisms and from the spatial organization of the constitutive elements. The activities concern both structure and functional materials with dominant mechanical investigations for the former ones (plasticity, damage and fracture) and dominant physical and chemical considerations for the latter ones (magnetism, optics, conductivity, thermodynamic stability, activity,...) but also crossed examinations of, possibly coupled, mechanical and physico-chemical properties. Studies of mechanical properties are mainly concerned with metallic materials (steel, aluminium alloys,...), metal-based composites (as metal-oxide compounds), compounds), with extensions to materials with particular architectures (involving closed or open porous phase or resulting from controlled - compacted or layer deposited - multi-phase assemblages for example). Elasticity, plasticity (up to large deformations), damage and fracture, but also recrystallization and microstructural transformations are the mainly investigated properties . Metal forming of flat products, growth and study of metallic single and multi- crystals (Cu, Al, Fe, Zr), measures and estimates of internal stresses in heterogeneous structures are recognized skills of the laboratory, as more recently the study of new (as ultra hard BCNx) compounds obtained under high pressure conditions, or materials obtained from chemical synthesis in (metallic, oxide, salt of hybrid) powder state. The shear loading test is one of the specials of the laboratory. Ultra finely grained metals and metal matrix composites obtained either by powder compaction techniques or by severe plastic deformation also is an axis of recognized expertise of the laboratory.

The increasing involvement of LSPM in the study and the modeling of finely structured materials, with complex architectures, towards the accounting of specific effects related to small dimensions, has led to develop nano-characterization in microscopy (electronic and atomic) and in diffractometry. Particularly involved in the study of a load on the physical properties of materials, LSPM has varied its means for examining loaded materials in situ of microscopy, diffraction, spectroscopy etc,

For which it conceives the testing micro-machines for tension, compression, bending and shear loading. Some of these machines can be operational on various devices, allowing multi-physic characterizations. Special machines for shear under high pressure between diamond anvil cells also are prototypically developed specialties.

3. Processes and characterization tools

LSPM possesses a large platform of elaboration processes allowing fabrication of a wide range of materials from single crystals to nanocrystals : sol gel, laser induced nucleation, CVD, plasma, .... In order to perform diagnostics of plasmas or of nucleation processes, LSPM have a Laser platform, being partly shared with LPL. An UV to visible Laser for plasma diagnostics together with a Labram spectrometer complete this Laser platform. LSPM has a structural characterization platform including X-Ray diffractometers, TEM, AFM, SEM. In addition, some specific equipments such as electronic conductivity and diamond view set-up. Unique facilities also exist that make possible the elaboration of nanostructured bulk materials such as ductile (super-plastic) material by processing copper nanoparticles under under high pressure and low temperature, crystal growth Bridgman and strain annealed methods and two Hot Isostatic Pressing devices, together with mechanical testing (2 shear testing devices, standard tensile and compressive testing, microindentor, image acquisition and analysis device for measures of kinematic fields),one symmetric and one non symmetric rolling devices. Means and equipments dedicated to specific studies are the Brillouin diffusion, high pressure (belt and multi-anvil) presses, the interferometry lasers and power lasers, ATDATG and equipments for chemical synthesis. Means for calculations and image analyses are available as well. Modeling the processes.